Synthetic jet actuators are a widely-used technology that generates a synthetic jet of fluid to influence the flow of that fluid over a surface to disperse heat away therefrom. A typical synthetic jet actuator comprises a housing defining an internal chamber. An orifice is present in a wall of the housing. The actuator further includes a mechanism in or about the housing for periodically changing the volume within the internal chamber so that a series of fluid vortices are generated and projected in an external environment out from the orifice of the housing. Examples of volume changing mechanisms may include, for example, a piston positioned in the jet housing to move fluid in and out of the orifice during reciprocation of the piston or a flexible diaphragm as a wall of the housing. The flexible diaphragm is typically actuated by a piezoelectric actuator or other appropriate means.
Typically, a control system is used to create time-harmonic motion of the volume changing mechanism. As the mechanism decreases the chamber volume, fluid is ejected from the chamber through the orifice. As the fluid passes through the orifice, sharp edges of the orifice separate the flow to create vortex sheets that roll up into vortices. These vortices move away from the edges of the orifice under their own self-induced velocity. As the mechanism increases the chamber volume, ambient fluid is drawn into the chamber from large distances from the orifice. Since the vortices have already moved away from the edges of the orifice, they are not affected by the ambient fluid entering into the chamber. As the vortices travel away from the orifice, they synthesize a jet of fluid, i.e., a “synthetic jet.”
It is recognized that vibration propagation and acoustic noise are negative aspects of synthetic jet operation. With respect specifically to vibration propagation, it is highly desirable to prevent vibrations from be transmitted from the moving surfaces of the synthetic jet to a mounting structure to which it is attached and/or passed on to the surrounding structures or surfaces the mounting structure is attached to. While providing a mounting structure that minimizes vibration propagation is achievable, such mounting structures also should be designed so as not to dampen the airflow output of the synthetic jet actuator, as can occur if the synthetic jet actuator is restrained rigidly to a fixed stationary surface.
It would therefore be desirable to provide a mounting structure that provides vibration dampening by limiting the amount of undesirable vibrations transmitted from the moving surfaces of the synthetic jet to the mounting structure and to the surfaces the mounting structure is attached to. It would also be desirable for the mounting structure to allow the synthetic jet to function with less dampening on the airflow output than if it was restrained more rigidly to a fixed stationary surface.